The present invention relates to controllers for providing actuation of a plurality of separate electrical switches for making and breaking circuits to separate control devices. Switch controllers of this type are employed for controlling the operation of certain emission control devices in response to throttle shaft movement on automotive internal combustion engines. It has been found convenient in the design of emission control systems for diesel engines to provide a coupling to the engine throttle shaft and to actuate certain emission control devices, such as, for example, exhaust gas recirculation (EGR) exhaust pressure relief (EPR) and Torque Converter Clutch (TCC) devices upon a predetermined movement of the engine throttle shaft.
Devices which are received over the end of the engine throttle shaft and which employ a rotating cam means to actuate a single electrical switch mechanism are known, as for example, the device described in a copending application Ser. No. 146,903 filed May 5, 1980, Fluid Pressure Liquid Signal Controller, and assigned to the assignee of the present invention.
However, in providing diesel engine emission control systems a need has arisen to provide for actuation of a plurality of separate electrical switch mechanisms in response to different predetermined amounts of rotation of an engine throttle shaft. In providing such emission control systems it has been found extremely difficult to provide a means of conveniently mounting the switch mechanisms in a manner which readily provides for separate calibration of the switch mechanisms with respect to the predetermined amount of rotation of the throttle shaft.
Furthermore, it has been desirable to provide for actuation of a plurality of electrical switch mechanisms in response to different amounts of rotation of an engine throttle shaft and to provide for accurate and convenient calibration of some of the switch mechanisms after the device has been installed on the vehicle engine. Thus, a need has arisen for a device which provides for separate actuation of a plurality of electrical switch mechanisms responsive to different degrees of rotation of an input shaft, as for example, a vehicle engine throttle shaft and provides for convenient and readily accessible field calibration of the device after installation. In addition, it has been desired to provide such a device with a readily accessible field calibration feature, yet provide calibration which would not change or shift during prolonged engine service.